Transporting bulldozers on the backs of low flatbed trucks has proven difficult especially for the larger bulldozer designs (for example, a Caterpiller Tractor, Model D-9 or larger) in which the blade of the bulldozer is of a width such that it protrudes substantially beyond the sides of the flatbed truck. In most states of the United States, to be legally driven on the back of a low flatbed truck, (ie: "street legal"), the sides of the bulldozer must typically not extend to a width greater than permitted under state and/or federal highway regulations.
Consequently, for large bulldozers, the blade must be disconnected from the bulldozer when the bulldozer is placed on the bed of the flatbed truck so that the bulldozer can be made street legal. The bulldozer blade is typically rotated by 90.degree. and placed either beside the bulldozer on the same flatbed truck or alternatively it is placed on a separate truck.
The removal of the blade from the bulldozer is no easy task. Often, such blades weigh up to 10,000 pounds, and the push arms, which also must be removed, can weigh 5,000 pounds or more. Thus, a crane or boom truck is required to lift and to move the blade and push arms while they are being disassembled from the bulldozer. This process is very time consuming, often requiring two men to work for as long as eight hours in order to ready the bulldozer for transport.
Another major problem with removing the blade and push arms from the bulldozer is that the hydraulic lift cylinders, which support and control the movement of the blade and push arms, typically will be unsupported and uncontrollable when detached from the blade. When the bulldozer blade is detached, the hydraulic cylinders can freely articulate and the pistons extend from the hydraulic cylinders such that the hydraulic assembly must be secured for transport. Accordingly, the blade hydraulic system typically is at least partially disassembled as part of the transport process.
A variety of devices do exist for mounting and manipulating the orientation of bulldozer blades. None of these devices, however, are adapted to hold the bulldozer push arms inwardly at an elevated position while simultaneously holding together the hydraulic lift cylinder assembly attached to the back of a bulldozer blade when the blade has been removed.
For example, U.S. Pat. No. 1,784,144 to Kerber discloses a bulldozer blade which is designed not to interfere with the use of a rear draw bar. U.S. Pat. No. 2,624,132 to Henry discloses a bulldozer attachment for tractors which is designed to equalize the vertical movement of the bulldozer blade along its length regardless of the forces which may be exerted on the blade by its contact with the ground. U.S. Pat. No. 2,659,572 to Steer discloses a tractor lifting apparatus which is attached to the front of the tractor thereby providing a low center of gravity enabling more effective pushing. U.S. Pat. No. 3,662,841 to Mobley, et al. discloses a bulldozer blade mounting system having an easily adjustable pitch. U.S. Pat. No. 4,135,584 to Smith, et al. discloses a bulldozer blade stabilizing linkage which prevents side forces exerted on the blade from shifting the blade by a distance whereby the lift linkages would come into contact with the tracks of the bulldozer. U.S. Pat. No. 4,147,218 to Stedman discloses a bulldozer attachment for a four-tracked tractor having a pair of push arms extending between respective pairs of track assemblies. U.S. Pat. No. 4,153,117 to Freese discloses a three point attachment support for a cushioned bulldozer blade. Lastly, U.S. Pat. No. 4,286,674 to Noble, et al. discloses a replaceable bearing assembly for use at the connection point between a bulldozer push arm and the side of the bulldozer. Unfortunately, none of these existing systems are adapted to solve the present problems which occur when the front blade is removed from a bulldozer in order to enable transport.